1. Field of the Invention
This invention generally systems for preparing and using stems cells derived from adipose tissue, adipose-derived stem cells obtained with such kit, methods of using such adipose-derived stem cells, compositions containing such adipose-derived stem cells.
2. Discussion of the State of the Art
Regenerative medicine can be defined as harnessing the body's regenerative mechanisms in a clinically targeted manner, using them in ways that are not part of the normal healing mechanism or by artificially amplifying normal mechanisms. One classic example of this process is found in bone marrow transplantation where hematopoietic stem and progenitor cells are harvested from a donor and placed into a recipient, in whom the normal hematopoietic regenerative mechanisms have been ablated or substantially depleted or impaired, thereby replacing or regenerating the blood-forming capacity of the recipient. This approach has been extended to the non-hematopoietic stem cells from a variety of sources for multiple therapeutic or prophylactic purposes. In particular, it has been demonstrated that adipose tissue can readily be used as a source of multipotent mesenchymal stem cells suitable for therapeutic or prophylactic use.
Mesenchymal Stem Cells (“MSCs”) are pluripotent stem cells that can differentiate readily into lineages including osteoblasts, myocytes, chondrocytes, adipocytes, endothelial cells, and beta pancreatic islet cells (Pittenger, et al., Science, Vol. 284, pg. 143 (1999); Haynesworth, et al., Bone, Vol. 13, pg. 69 (1992); Prockop, Science, Vol. 276, pg. 71 (1997)). MSCs, also known in the literature as bone marrow stem cells, skeletal stem cells, and multipotent mesenchymal stromal cells, are non-hematopoietic progenitor cells isolated from adult tissues, and are characterized in vitro by their extensive proliferative ability in an uncommitted state while retaining the potential to differentiate along various lineages of mesenchymal origin, including chondrocyte, osteoblast, and adipocyte lineages, in response to appropriate stimuli. In vitro studies have demonstrated the capability of MSCs to differentiate into muscle (Wakitani, et al., Muscle Nerve, Vol. 18, pg. 1417 (1995)), neuronal-like precursors (Woodbury, et al., J. Neurosci. Res., Vol. 69, pg. 908 (2002); Sanchez-Ramos, et al., Exp. Neurol., Vol. 171, pg. 109 (2001)), cardiomyocytes (Toma, et al., Circulation, Vol. 105, pg. 93 (2002); Fakuda, Artif. Organs, Vol. 25, pg. 187 (2001)) and possibly other cell types. MSCs are present in multiple tissues in the body, which arise from the embryonic mesoderm (e.g., hematopoietic cells and connective tissue). As such, pluripotent cells can be isolated from any of these tissue sources and can be induced to differentiate into any of these cell types.
A convenient source of adipose tissue is from liposuction surgery. In fact, a large quantity of pluripotent cells can be obtained by simple aspiration from adipose tissue, for example, from lipoaspirate samples from aesthetic interventions. The present invention is directed in particular to a system for isolating MSCs from adipose tissue. As used herein, “adipose tissue” refers to a tissue containing multiple cell types including adipocytes and microvascular cells. Adipose tissue includes stem cells and endothelial precursor cells. Accordingly, adipose tissue refers to fat including the connective tissue that stores the fat.
It has been discovered that adipose tissue is an especially rich source of stem cells. This finding may be due, at least in part, to the ease of removal of the major non-stem cell component of adipose tissue, the adipocyte. However, processing of adipose tissues to separate pluripotent cells and expansion and (optionally) differentiation of the resulting stem cell population, according to systems and methods known in the art, generally requires expensive, specialized equipment and equally expensive, specialized processes. The costs associated with purpose-built devices for repeated stem cell extraction from adipose tissues obtained by, for example, liposuction from a living human donor have restricted the use of stem cell-rich media for therapeutic purposes to large hospitals and research facilities. As a result, use of adipose-derived stem cell-based therapies by small physician or other professional practices has not been possible or economical. Moreover, use of stem cell-based cosmetic enhancement techniques has been hampered by the high cost and low availability of systems and methods currently in the art for extracting and culturing stem cells derived from adipose tissues.
What is needed are techniques and systems that facilitate economical and safe extraction of therapeutically or cosmetically useful quantities of adipose-derived stem cells, whether in pure form or as part of a stem cell enriched medium, and specifically techniques and systems that are suitable for use in small professional practices without requiring capital investments of specialized facilities.